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Biomedical subjects

W H Chen

Publications and source records attributed to W H Chen.

At least 55 records · Page 3Linked to original sources
PubMed1999

Combining qualitative with quantitative approaches to study contraceptive pill use.

According to large-scale studies, oral contraceptive users become pregnant at rates that exceed ideal use failure rates. It is thought that a major cause is missed pills, but current research on consistent contraceptive pill taking is characterized by inadequate measures and a failure to investigate women's thinking about their own patterns of use. The purpose of this study was to gain some understanding about women's interpretations of consistency in their own pill taking through combining qualitative with quantitative data. The study was conducted in China, where contraception is free and widely available. Five urban and five rural oral contraceptive users were followed for up to three pill-taking cycles during 1996 for a total of 759 person-days. Consistency of pill taking was measured with electronic data obtained from a new blister package made by Anderson Clinical Technologies (Elmhurst, IL). Data from these devices were reviewed and interpreted by the study participants during in-depth private interviews. The users' reasons for missing pills included disruptions in their daily routines, their husband's absence, spotting, and trouble implementing the family planning program's instructions to take one pill per day for 22 days and start the next cycle on the fifth day of menses. One user gave these reasons for two cycles but denied missing numerous pills in her third cycle. Data from a series of four questionnaires showed that most demographic, psychosocial, and service system characteristics were not related to missed pills. However, results suggested that the daily routines of rural living may make consistent use more likely and that instructions for taking the pill may be associated with prolonged pill-free intervals and skipping pills during episodes of spotting. Three of the 10 women were at increased risk of pregnancy during the study period because of their pill-taking pattern. We concluded that the combination of qualitative with quantitative data enhances understanding of contraceptive use. Women themselves offer plausible reasons for their use behaviors. Listening to women could be useful in improving programs.

Adolescent↗
PubMed1999

Novel role of the Ca(2+)-ATPase in NMDA-induced intracellular acidification.

The mechanism involved in N-methyl-D-glucamine (NMDA)-induced Ca(2+)-dependent intracellular acidosis is not clear. In this study, we investigated in detail several possible mechanisms using cultured rat cerebellar granule cells and microfluorometry [fura 2-AM or 2', 7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein-AM]. When 100 microM NMDA or 40 mM KCl was added, a marked increase in the intracellular Ca(2+) concentration ([Ca(2+)](i)) and a decrease in the intracellular pH were seen. Acidosis was completely prevented by the use of Ca(2+)-free medium or 1,2-bis(2-aminophenoxy)ethane-N,N,N', N'-tetraacetic acid-AM, suggesting that it resulted from an influx of extracellular Ca(2+). The following four mechanisms that could conceivably have been involved were excluded: 1) Ca(2+) displacement of intracellular H(+) from common binding sites; 2) activation of an acid loader or inhibition of acid extruders; 3) overproduction of CO(2) or lactate; and 4) collapse of the mitochondrial membrane potential due to Ca(2+) uptake, resulting in inhibition of cytosolic H(+) uptake. However, NMDA/KCl-induced acidosis was largely prevented by glycolytic inhibitors (iodoacetate or deoxyglucose in glucose-free medium) or by inhibitors of the Ca(2+)-ATPase (i.e., Ca(2+)/H(+) exchanger), including La(3+), orthovanadate, eosin B, or an extracellular pH of 8.5. Our results therefore suggest that Ca(2+)-ATPase is involved in NMDA-induced intracellular acidosis in granule cells. We also provide new evidence that NMDA-evoked intracellular acidosis probably serves as a negative feedback signal, probably with the acidification itself inhibiting the NMDA-induced [Ca(2+)](i) increase.

Acidosis↗
PubMed1999

The presentation of serum lipids and uric acid in cerebral ischemia.

In this study, we examine the relationship between serum lipids and uric acid in nonembolic cerebral ischemia (NECI) patients. The serum level of total cholesterol (TC) and uric acid increased significantly in male, while TC and triglyceride in female patients. The increase of TC was more significance in female patients. There was no correlation between serum lipids and uric acid in NECI patients or controls, but a significant correlation between triglyceride and uric acid was present in diabetic patient. These findings suggest that lipids and uric acid are essential risk factors for cerebral ischemia in our population. Although there is no association of their metabolism, their parallellic abnormality in diabetic NECI individuals indicates that some possible factors changing in diabetics can influence the metabolic pathway of both lipid and uric acid, which may promote each other for atherogenesis in diabetics.

Aged↗
PubMed1999

Rapid progression of parkinsonism associated with an increase of blood manganese.

In this paper, we report a 72-year-old man whose parkinsonian pictures accelerated rapidly after an ingestion of unknown herb pills. His serum manganese and aluminum level increased 2-fold and 5-fold over physiological level respectively. A reverse of his parkinsonian deterioration was accompanied with a normalization of these metals. Exclusive heavy metals have been widely mentioned in parkinsonism. While industrial source of these metals has extensively been sought, pharmacology is rarely mentioned in this aspect, especially of herb medicine origin. We suggest that an acceleration of parkinsonian pictures should raise the need to re-evaluate the possibility of heavy metal intoxication in parkinsonism. Besides of industrial contamination, we should be alert for the nonindustrial source in our population.

Aged↗
PubMed1999

Florid osseous dysplasia: case report.

Florid osseous dysplasia (FOD) is a benign, non-neoplastic lesion characterized by multiple sclerosing masses only within the jawbones. It is most prevalent in middle-aged black women but uncommon in Orientals. Most cases are asymptomatic and should be left untreated. However, the jawbone involved in FOD is very susceptible to infection, including osteomyelitis developed from periodontitis, pulpopathosis, bone biopsy, wearing removable partial dentures, root canal therapy, tooth extraction, inappropriate dental treatment, etc. If secondary osteomyelitis develops, antibiotic and conservative dental therapy treatment is recommended for removing the sources of the odontogenic infection. Surgical removal of inflamed masses is indicated if the inflammatory signs and symptoms are persistent after antibiotic and conservative dental therapy. Here we report a rare FOD case in which an osteomyelitis resulting from generalized periodontitis and bone biopsy was triggered. The patient was accepted for surgery and follow-up in our department. The current literature of this disease is reviewed as well, focusing especially on the clinical manifestations, radiographic features, differential diagnosis, and treatment.

Diagnosis, Differential↗
PubMed1999

Fetal Doppler hemodynamic changes in spontaneous versus prostaglandin E1-induced active labor.

BACKGROUND: To assess fetal hemodynamic changes before and during active labor, either spontaneous or prostaglandin E1 (PGE1)-induced labor. MATERIALS AND METHODS: This is a prospective longitudinal study and a cohort of 49 healthy women at 37-41+ weeks gestation without signs of fetal distress was investigated until in labor. One group of 23 healthy women had spontaneous active labor, the second group of 26 women was in active labor induced by an intra-cervical administration of PGE1 for elective induction. Blood flow waveform indices (S/D ratio, RI, PI) were assessed by pulsed Doppler ultrasonography from the umbilical artery (UA) and fetal middle cerebral artery (MCA) before and in labor. Both groups were compared for the waveform indices and perinatal outcome including duration of labor, meconium stain, baby sex, birthweight, UA blood gas measurements at delivery, Apgar's scores, prolonged nursery stay (> or =5 days), and NICU admission. RESULTS: Demographic data of the two groups were comparable. During spontaneous active labor, the S/D ratio and RI became significantly decreased in the UA (p<0.05) and the three wave-form indices were decreased more in the MCA (p<0.01, 0.005, 0.05, respectively) compared with those measured before labor. During PGE1-induced active labor, all the waveform indices were not significantly decreased in either the UA or the MCA. The occurrence of abnormal UA blood gas values was significantly more in the PGE1-induced group than in the spontaneous labor group (23.1% v.s. 4.3%; p<0.05). No other adverse perinatal outcomes were observed in either group. CONCLUSIONS: Decreasing impedance in both the UA and MCA during spontaneous labor is a physiological fetal adaptation to labor to prevent fetal cerebral hypoxia by maintaining adequate brain blood flow during normal parturition. This fetal adaptation phenomenon was not observed in the group of PGE1-induced labor with the result of a high incidence of abnormal UA blood gas values.

Adult↗
PubMed1999

Rhinosino-orbital mucormycosis causing cavernous sinus thrombosis and internal carotid artery occlusion: radiological findings in a patient with treatment failure.

The authors describe a case of rhinosino-orbital mucormycosis with cavernous sinus thrombosis in association with internal carotid artery occlusion diagnosed by use of computerized tomography (CT) and magnetic resonance imaging (MRI). Cranial CT is a useful imaging tool in the diagnosis of rhinosinal invasive fungal disease and MRI offers excellent aid in the detection of intracranial extension. Early diagnosis and rapid institution of surgical debridement and antifungal therapy is the rule of thumb in treating this disorder. In our patient, surgically inaccessible bone lesion and involvement of the central nervous system are taken as major causes for his grave outcome. In addition, failure to advance appropriate amphotericin B dosage may also make the infectious process uncontrollable in this patient.

Carotid Artery Thrombosis↗
PubMed1999

Intracranial fatigable ptosis.

Two patients sought treatment for bilateral fatigable ptosis; one patient had a hematoma, and the other patient had an intracranial metastasis. Compression of the central caudal nucleus in the dorsal midbrain is proposed as the cause of this ptosis, and an alteration of central acetylcholine neurotransmission may contribute to ocular fatigability. Because symptoms that suggest fatigable ptosis can be similar to those that suggest ocular myasthenia gravis, a careful evaluation is necessary to avoid misinterpretation.

Adult↗
PubMed1999

The role of gastric acid and Helicobacter pylori in the natural course of duodenal ulcer.

This study was conducted using roxatidine acetate or Mylanta combined with metronidazole and amoxicillin to evaluate the role of acid and Helicobacter pylori in the natural course of the duodenal ulcer. Eighty-three patients with H. pylori positive duodenal ulcers were randomly allocated into one of four treatment groups. Group A: roxatidine 75 mg hs for 8 weeks; Group B: the same as group A + metronidazole 250 mg and amoxicillin 250 mg qid for 1 week on the 3rd week; Group C: Mylanta (combined hydroxide of magnesium and aluminum) 20 ml qid for 8 weeks; Group D: the same as group C + metronidazole 250 mg and amoxicillin 250 mg qid for 1 week on the 3rd week. Repeated endoscopies were performed on the 8th week post the initial treatment and the sixth and 12th month post the termination of treatment, or, at the earliest recurrence of symptoms. Eradication of H. pylori was considered to be successful if the culture, histology and CLO test all showed negative. The ulcer healing rates of Groups A, B, C and D were 95%, 100%, 61% and 86%, respectively, with a significant difference between A and C. The eradication rates of groups B and D were 81% and 62%, respectively, without any significant difference. The 12 months cumulative ulcer recurrence rates were 72%, 15%, 80% and 22%, respectively, with a significant difference between each paired groups with and without antibiotics. In conclusions, roxatidine is effective in the healing of duodenal ulcer. One-week roxatidine-based triple therapy is powerful in the eradication of H. pylori. Potent acid suppression is sufficient to heal the duodenal ulcer. Eradication of H. pylori can potentiate ulcer healing under insufficient acid suppression. A causal role for H. pylori in recurrent duodenal ulcer is strongly supported by a much lower recurrence of ulcer in H. pylori free patients.

Adolescent↗
PubMed1999

Three-dimensional computer-assisted simulation combining facial skeleton with facial morphology for orthognathic surgery.

The purpose of this study was to use a 3-dimensional (3D) computer-aided design (CAD) simulation system to plan surgical procedures and predict postoperative changes in orthognathic surgery patients. A computer-generated imaging model was developed by combining a 3D reconstructed cephalometric skeletal image and a laser-scanned facial surface image. Moreover, postoperative data were studied and linked to the simulator model for programming and executing simulated surgical procedures. Interactive editing capabilities allow surgeons to operate CAD surgical simulation, and predicted results can be presented graphically and numerically. The results indicate that the integration of 3D images and CAD techniques have a potential for simulating surgery and providing graphic information to patients in obtaining an informed consent.

Adult↗
PubMed1999

[HRV analysis system based on Windows 95 and its preliminary application].

Objective. To provide a real useful application system for the HRV research. Method. The acquisition, detection and analysis system of HRV signal was set up based on Windows 95. The system analyzes the HRV signal with statistic method in time domain and power spectrum in frequency domain. And the power spectrum array was also introduced into the analysis. HRV signals of some healthy persons and some patients were detected and analyzed. Result. The HRV characteristic is much more obvious in the diabetics patients. Conclusion. The system is useful in HRV signal analysis and cardiovascular research.

Aerospace Medicine↗
PubMed1998

IGF I induction of p53 requires activation of MAP kinase in cardiac muscle cells.

The aim of this study was to investigate whether IGF I induction of p53 expression and p21 promoter require activation of MAP kinase in cardiac muscle cells. Compared to cardiomyocytes transfected with control vector, activation of MAP kinase by IGF I was decreased by approximately 60-70% in the cells transfected with dominant negative MAP kinase Y185. Transfection with Y185 also resulted in decreased induction of p53 mRNA by IGF I (70% reduction). In the cells transfected with a wildtype p21WAF1/CIP1 promoter construct, activation of luciferase reporter gene by IGF I was decreased in the cells co-transfected with Y185. To further confirm these findings, cells were preincubated with PD98059, a specific MAP kinase kinase inhibitor. As expected, PD98059 inhibited induction of p53 mRNA and p21WAF1/CIP1 promoter by IGF I. These data indicate that transcriptional activation of p53 and p21WAF1/CIP1 by IGF I involves MAP kinase pathway in cardiomyocytes, and thus link MAP kinase to negative modulation of the cell cycle in cardiac muscle cells.

Animals↗
PubMed1998

Application of the surface rendering technique of three-dimensional ultrasound in prenatal diagnosis and counselling of Klippel-Trenaunay-Weber syndrome.

Klippel Trenaunay-Weber syndrome is a complex developmental disorder characterized by a triad of cutaneous haemangioma, varicosities of the body, and unilateral limb hypertrophy. We describe the prenatal diagnosis of Klippel-Trenaunay-Weber syndrome at 15 weeks' gestation using the surface rendering technique of three-dimensional ultrasound. The vivid three-dimensional images of the affected fetus are invaluable in prenatal diagnosis and parental counselling.

Adult↗
PubMed1998

Stenting of a renal artery bifurcation stenosis.

Renal artery stenosis involving the renal artery ostium often responds suboptimally to balloon angioplasty. In this context, immediate and long-term results can be optimized by stenting. Occasionally, lesions may involve the midartery segment at a branch point. We report a case of a bifurcation lesion which responded poorly to balloon angioplasty despite the kissing balloon technique. Excellent angiographic result was finally achieved by deploying two flexible coil stents in a "kissing" fashion. The patient's hypertension came under control overnight. At 6-month follow up, he remained normotensive on no medication. Repeat renal angiogram also showed no restenosis.

Adult↗
PubMed1998

Neonatal gastric aspirates as a predictor of perinatal hepatitis B virus infections.

OBJECTIVE: To elucidate possible routes and predictors of perinatal transmission of hepatitis B virus (HBV). METHOD: This was a prospective follow-up study. One hundred and forty-seven out of 1762 pregnant women who were screened in the antenatal clinic of a university teaching hospital were HBsAg carriers. Enzyme immunoassay was used for determination of hepatitis B markers. Occurrence of HBsAg in newborns' gastric aspirates, newborns' and infants' blood, and maternal milk samples were determined. Their relationship with delivery routes and duration of the first stage of labor were analyzed by chi square test. RESULTS: The presence of HBsAg in newborns' gastric aspirates was strongly associated with the acquisition of HBsAg by the babies. There was no correlation between the rate of infant antigenemia and the duration of the first stage of labor, nor did cesarean section decrease the rate of vertical transmission of HBV. CONCLUSIONS: This is the first report to provide direct evidence for the major role of the oral route in vertical transmission of HBV during delivery. In addition to maternal serum HBeAg, HBsAg status in newborn's gastric aspirates is another important determinant for vertical transmission of HBV.

Biomarkers↗
PubMed1998

Extra-amniotic balloon with PGE2 versus extra-ovular Foley catheter with PGF2alpha in mid-trimester pregnancy termination.

OBJECTIVE: The objective of this study was to compare the efficacy and side effects of two methods of mid-trimester labor induction, extra-amniotic balloon with intracervical prostaglandin (PG) E2 (0.5 mg x 2) vs. extra-ovular Foley catheter with intrauterine PGF2alpha (1 mg/h x6). METHODS: A cohort of 32 and 36 cases indicated for mid-trimester termination was enrolled and managed with extra-amniotic balloon and extra-ovular Foley catheter methods, respectively. Outcomes of induction-to-delivery interval, induction failure, and occurrence of side effects were assessed. RESULTS: There were no statistical differences in maternal age, parity, gestational age or fetal birth weight between the two groups. Compared with the extra-ovular Foley catheter with PGF2alpha group, the induction-to-delivery interval was significantly shorter in the extra-amniotic balloon plus PGE2 group. There was no significant difference in side effects and major complications developed in either groups. CONCLUSIONS: The extra-amniotic balloon with intracervical PGE2 is more efficient in reducing the induction-to-delivery interval for termination of mid-trimester pregnancies than the extra-ovular Foley catheter with intrauterine PGF2alpha.

Abortion, Induced↗